Golubev et al. (U.S.S.R. Inventor Certificate No. 341,788, published Jul. 7, 1972) describe a liquid phase process for producing 1,1-difluoroethane (HFC-152a) by reacting chloroethene with hydrogen fluoride (HF) while in the presence of tin tetrachloride (SnCl.sub.4).
Komatsu et al. (European Patent EP 187,643, filed Jan. 3, 1986) discloses a process for manufacturing hydrofluorocarbons by reacting hydrochlorocarbons with HF while in the presence of a tin catalyst and an additive chosen from compounds containing oxygen or nitrogen. These additives, however, have low stability in the reaction medium and/or reduce the activity of the tin catalyst when used in the presence of HF and a hydrochlorocarbon such as 1,1,2-trichloroethane.
U.S. Pat. No. 4,968,850 to Franklin et al., discloses a process for manufacturing a fluorinated hydrocarbon by reacting hydrogen fluoride with an unsaturated chlorinated hydrocarbon while in the presence of a tin catalyst.
Komatsu et al. (Japanese Kokai publication number SHO 621987!-246528, publication date Oct. 27, 1987) describes a process for manufacturing hydrofluorocarbons, characterized by reacting a hydrogen-containing halogenated hydrocarbon with HF in a liquid phase.
The disclosure of the above-identified patent documents is hereby incorporated by reference.